WO2001032078A1 - The control method and system and the sense organs test method and system based on electrical steady state induced response - Google Patents

Abstract

A control method and a sense organ test method based on electrical steady state response of brain include the steps of producing one or more stimulate signals sensed by sense organs of human subject and varied at different frequencies; detecting the brain electrical signal of stimulated human subject; analyzing the detected brain electrical signal in which characteristic physical parameters in correspondence with a stimulate signal frequency is selected; based on this characteristic physical quantity, a controlled device in correspondence with the stimulate signal performs a prearranged operation or estimates objectively the sense condition of the subject.

Description

 Controller based on EEG steady state evoked response

 Method and system and sensory test method and system Field of the invention

 The invention relates to a method and a device for controlling a computer and other equipment based on a brain electrical signal, and in particular, to a method and a device for controlling a computer and other equipment based on an EEG steady state evoked response, and a method based on EEG stabilization. Method and device for objectively testing sensory responses of state-induced responses. Background technique

 The brain-computer interface is a direct communication and control channel established between the human brain and a computer or other electronic device. Through this channel, people can express ideas or manipulate devices directly through the human brain, without the need for language or body movements.

 The main difference between a brain-computer interface and ordinary human-machine interfaces is that the former does not require any kind of muscle response, but only needs to detect signals that reflect the responsiveness or purposeful activity of the brain

 The control device based on the brain-machine interface can achieve the control purpose without any language or body movement.

 The main difference between objective sensory test systems based on the brain-machine interface and those subjective sensory test systems is that the former does not require the expression of subjective consciousness or behavior such as language or body movements. It only needs to detect the response or purpose of the human brain The signals of sexual activity are therefore objective and fair.

 The more direct methods to achieve EEG control are:

 (1) Method based on event-related EEG signals

 For example, before a person's autonomous movement occurs, there is an event-related desynchronization component associated with the movement in the EEG, which is essentially an induced EEG signal. People can

1

Confirm this Event-related signals are identified in the recorded EEG signals and used to achieve some control.

Pfurtschel ler and others conducted a series of BCI studies based on this physiological phenomenon. The subjects faced a target displayed on the right or left side of the display. The subject prepared to press with the left or right index finger according to the position of the target A switch, after about a second, a cross-shaped cursor appears in the center of the display, and the subject pressed the switch. The EEG signal used for classification is the action preparation stage after the target appears and before the cursor appears. Learning is used to obtain a template to predict whether it is right-hand or left-hand movement (see "Brain- computer Int erface-A New Communication Device for Handicapped Persons" J Microcomput Appl, 1993, 16: 293-299; "Prediction of the Side of Hand Movements from Single Trial Multichannel EEG Data Using Neural Networks", Electroenceph Cl in Neurophs iol, 1992, 82: 313-315).

 (2) Method based on inducing EEG signals

 Figure 1 shows a schematic diagram of a prior art system that performs some control based on evoked EEG signals. This method is to give the subject a certain stimulus, record the EEG signals induced under different stimuli, identify them, and then use the identified signals to achieve some control.

 P300 is a type of event related potential (ERP), and a peak of 300 mg of EEG will be called P300 after a related event occurs. Farwel l and Doncin designed a virtual printer using ERP. A 6 X 6 character matrix blinks randomly in rows or columns, then "the row or column containing the character that the user wants to enter blinks" becomes a related event. Find the row and column that cause the largest amplitude of P300, then the characters to be printed at the intersection of the row and the column.

Sutter's BCI system uses the visual evoked potential (VEP) method. The 8 × 8 symbol matrix on the display is red / green alternated according to a pseudo-random binary sequence. The user looks at the symbol to be selected and compares the measured EEG signal with a previously recorded template. The goal. Learning a stable template beforehand is a key step (see "The Brain Response interface: Communicat ion through Visual ly-induced Electrical Brain Response ", J Microcomput Appl, 1992, 15: 31-45).

 The above system uses the transient evoked response of the EEG. Since the test is based on P300, the time interval between two stimuli is required to be greater than 1 second to ensure that the subject responds to the previous stimulus before the new stimulus arrives. The response has ended or disappeared. Therefore, the above system cannot be used for real-time control, and the reliability of its test cannot meet the practical requirements

 Another major shortcoming of the current brain-machine interface method as a detection technology is that sensory stimulation methods with or without spatial information can not be given at the same time, so the detection results do not have the spatial resolution information of the sensory system, and the application range is greatly limited. Object of the invention

 An object of the present invention is to provide a reliable control method and system based on the EEG steady state evoked response, which can not only achieve a high judgment accuracy rate, but also ensure real-time performance in use.

 Another object of the present invention is to provide a sensory test method and system based on EEG steady state induced response, which can objectively evaluate the state of the senses. Summary of the invention

 The basis of the present invention is the steady state induced response to EEG. The so-called steady-state EEG response means that when the stimulation frequency is greater than a certain value, the subject's EEG response will be aliased back and forth, resulting in a periodic change in the EEG evoked potential. The frequency of the periodic change is consistent with the stimulus frequency. Taking visual evoked response as an example, if the stimulation frequency is more than 6 times per second, the subject's visual evoked potential will have a periodic change in the corresponding frequency. Using EEG steady state evoked response to test the brain activity of the subject, the accuracy rate and test speed have reached a level that can be used for real-time control.

According to an aspect of the present invention, a control method based on an EEG steady state response is provided, including: a. Generate one or more stimulus signals that change at different frequencies and can be sensed by the human senses;

 b. Detecting EEG signals of the stimulated human body;

 c. Analyze the detected EEG signals, and extract a characteristic physical quantity corresponding to the frequency of a certain stimulus signal as a control signal;

d, the control signal based on the stimulation ^fe a particular controlled device performs a signal corresponding to a predetermined operation, ie.

 According to another aspect of the present invention, a sensory test method based on EEG steady state response is provided, including:

 a. Stimulate the subject's senses with one or more stimulation signals that can be sensed by the human senses at different frequencies;

 b. Detecting EEG signals of the stimulated human body;

 c Analyze the detected EEG signals and detect the characteristic physical quantity corresponding to the frequency of the stimulus signal;

 d. Evaluate the sensed sensor based on the detected physical quantities corresponding to the frequency of the stimulus signal, and the stimulus signal strength and spatial distribution.

 According to still another aspect of the present invention, a control system based on an EEG-induced steady state response is provided, including:

 a. a stimulator for generating one or more stimulus signals that change at different frequencies and can be sensed by human senses;

 b. EEG signal detector, which is used to detect the EEG signal of the stimulated human body;

 c a signal processor, configured to analyze the detected EEG signal, and extract a characteristic physical quantity corresponding to a certain stimulation signal frequency as a control signal;

 d. The control device controls a specific controlled device corresponding to the stimulation signal to perform a predetermined operation based on the control signal.

According to yet another aspect of the present invention, a sensory test system based on an EEG-induced steady state response is provided, including: a. a stimulator for generating one or more stimulus signals that change at different frequencies and can be sensed by human senses;

 b. an electroencephalogram signal detector for detecting an electroencephalogram signal of a human body stimulated by the stimulus signal;

 c. A signal processor, configured to analyze the detected EEG signal, and extract a characteristic physical quantity relative to the frequency of the stimulation signal from the signal processor;

 d. An evaluation device is configured to evaluate the response ability of the measured sensor to the stimulus signal based on the obtained physical quantity corresponding to the frequency of the stimulus signal and the spatial distribution characteristics of the stimulus signal, so as to obtain an objective evaluation of the sense organ.

 In one embodiment, the stimulation signal is a visual stimulation signal, and the human sense organ is a visual organ.

 In another embodiment, the stimulation signal is an auditory stimulus signal, and the human senses are auditory organs.

 In yet another embodiment, the stimulation signal is a tactile stimulation signal, and the human senses are tactile organs.

 Preferably, the analysis includes performing spectrum analysis on the EEG signal, and the characteristic physical quantity is a spectral component in the EEG signal spectrum corresponding to the frequency of each stimulus signal.

 In one embodiment, the stimulus signal is of a single frequency.

 In another embodiment, the one stimulus signal is a combination of multiple frequency signals.

 Potential applications of the invention are:

 (1) Provide a way for people with normal thinking and motor dysfunction to communicate and control the external environment. For example, they can control their wheelchair, functional electrical stimulation system, or computer through a brain-computer interface.

 (2) Provide a way for people to control external devices in special circumstances. Such as pilots under high acceleration;

(3) Provide a new way of entertainment for people. If you play video games with your mind, Synthetic music, etc.

 (4) Provide an objective vision or hearing detection method, without the need to express subjective conscious behaviors such as language or body movements. Its objectivity and impartiality overcome the artificial randomness in the measurement of traditional vision or hearing.

 (5) To provide people with an analysis of visual consciousness under special circumstances. Such as pilots at high degrees, tired or alcoholic drivers, etc. Brief description of the drawings

 FIG. 1 is a schematic diagram of a prior art test system based on evoked EEG signals. Fig. 2 is a schematic diagram showing the actual configuration of a control system based on the steady-state EEG response of the present invention.

 Fig. 3 is a circuit block diagram of a control system based on a steady-state EEG response of the present invention.

 FIG. 4 is a schematic diagram showing the actual configuration of a sensory test system based on a steady-state EEG response of the present invention.

 FIG. 5 is a circuit block diagram of a sensory test system based on a steady-state EEG response of the present invention. Preferred embodiment of the invention

 Hereinafter, the presently preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

 Figures 2 and 3 show a control system based on the steady-state EEG response of the present invention. The system is mainly composed of the following four parts:

(1) Stimulator

The role of the stimulator is to generate stimulation signals to the human sense organs. The stimulation signal may be a visual stimulation signal, an auditory stimulation signal, or a tactile stimulation signal. Taking visual stimulation as an example, the stimulator is composed of some stimulation points, and the stimulation points are light sources that flicker at a certain frequency. Stimulate The point can be a flash, other light source with a certain brightness, or a flickering light spot on the computer screen. The flicker mentioned here means that the brightness, shape, color, size, spatial position, duration, or combination of these physical quantities of the optical signal changes at a certain frequency. The frequency of change of the visual stimulus signal is generally in the range of 1 to 50 Hz, and preferably in the range of 4 to 25 Hz.

 A stimulus point can flash at a single frequency, or it can contain multiple signals that flash at different frequencies. The advantage of a stimulus point containing multiple signals of different frequencies is that the characteristics of the stimulus point in the subject's EEG are reflected as the combined frequency spectrum of the multiple frequencies, which allows more stimulus points to be set within a certain frequency range .

 The stimulator may include a stimulus controller for controlling the characteristics of the stimulus point. Taking visual stimulation as an example, the characteristics of the stimulation points are: 1. According to different requirements of the visual system measurement, the pre-stimulation before light stimulation is given. 2. Set the background of the light stimulus. 3. Set the parameters of the light stimulation points (such as spatial position, intensity, area size, and duration) for different flicker frequencies.

(2) EEG extraction, amplification and transmission

 The function of EEG extraction, amplification and transmission is to amplify the weak EEG signal to a sufficiently large amplitude, and convert it from analog to digital, and finally input it to a computer or other signal processing device. It includes the following sections.

 a. Electrode: An electrode is a metal sheet that is closely attached to the scalp. It can detect potential changes on the scalp surface (this change reflects electrical activity in the brain). The potential change on the electrodes is the input signal to the EEG amplifier. Its signal amplitude is l ~ 10uV.

 b. EEG signal amplifier: The function of the EEG amplifier is to amplify the weak EEG signal to a sufficiently large magnitude so that it can be converted from analog to digital. EEG amplifiers generally require an electrophysiological signal amplifier with a gain of 3000 to 10,000 times and a frequency passband of 1 to 30 Hz.

c. Signal transmission device: The signal transmission device refers to transmitting the digitalized EEG signal to a computer or other signal processing device. The transmission process can be wired or So wireless transmission. The transmission delay of the signal should be less than 10 ms. (3) EEG signal processor

 Electrophysiological experiments have proven that when the sensory organs of the human body are stimulated to a certain extent, as long as the subject's sensory system is healthy, the subject's occipital scalp can be recorded with distinctively induced EEG signals. The characteristics of the recorded signal appear in the time, space, and frequency domains. The function of the EEG signal processor is to analyze the characteristics of the EEG signal and identify these characteristics for control and other purposes.

 Taking steady-state visual stimulation as an example, the main functional modules in the EEG signal analyzer are: a. EEG signal preprocessing: Because the recorded EEG signal is very weak, interference is usually introduced during the extraction process. Therefore, pre-processing such as noise reduction must be performed before analysis. The noise to be removed is mainly the common frequency interference, baseline drift and so on. The method used is digital filtering.

 b. EEG signal spectrum analyzer: Take steady-state visual induction as an example, the stimulus point flashes a light source at a certain frequency, and the induced EEG includes the stimulus frequency and its harmonic components. In order to obtain these frequency components, the signal must be processed Spectrum analysis, this is the function of the frequency analyzer.

上式中 x (n)是数字化的脑电信号， η=0〜Ν-1 ; X籠是 x (n)的 离散傅里叶变换， k=0〜N-l。 Spectrum analysis is usually performed by a computer or other digital signal processor. Therefore, this is a digital signal processing process. The commonly used algorithm to complete the spectrum analysis is the fast Fourier transform (FFT). Its calculation formula is

In the above formula, x (n) is a digital EEG signal, η = 0 ~ N-1; X cage is a discrete Fourier transform of x (n), k = 0 ~ Nl.

c. Frequency characteristic analysis: In order to achieve different control requirements, the stimulus points can be designed to flicker at different frequencies or frequency combinations. When the subject looks at a certain stimulus point as required, the induced electroencephalogram should include the flicker frequency of the stimulus point and its harmonic components. For example, the frequency of the flicker of the stimulus point is a combination of multiple frequencies, and the induced EEG should also include non-linear components (such as sum and difference frequencies) of the frequency combination of the flicker of the stimulus point. From the frequency The different frequency components are distinguished in the analyzer, and the stimulus point or multiple stimulus points that the subject is watching can be realized. How to effectively distinguish the existence of stimulus frequency components from the frequency analysis results, the frequency characteristic analysis needs to solve the two problems of spectral peak resolution accuracy and spectral peak discrimination threshold. Our solution is (1) In order to improve the resolution of spectral peaks, the length of the FFT data should be a certain length, usually 1 second. (2) In the FFT result, if a peak occurs at a certain stimulus frequency, and the ratio of the peak amplitude to the maximum value of the FFT result at 4 to 35 Hz exceeds 0.8, the subject is considered to be watching If there is more than two stimulation frequencies that meet the conditions, the frequency with the highest ratio is used.

(4) Controller

 EEG signals with certain characteristics can be used to achieve certain control purposes after being identified.

 A typical application of the brain-machine interface is for the disabled to control the surrounding environment, for example, turning on / off the lights, turning on / off the TV, turning on / off the fans, and so on. From the output of the EEG signal processor, we can know which blinking light the subject is watching, and then we know what control we want to accomplish. As long as this information is transmitted to the environmental controller and the corresponding circuit is connected, the control of the surrounding electrical appliances can be realized.

 An example of the control system based on the EEG steady-state response of the present invention is shown in FIG. 2. The stimulator is a screen with four light spots on it, corresponding to the four pieces of electrical equipment to be controlled. The four light spots flicker at different frequencies. When the user looks at the light spot corresponding to the electric appliance to be controlled, the EEG signal processor can detect the frequency peak corresponding to the light spot in the EEG signal and output a corresponding signal to the controller. The controller controls the corresponding appliances to perform predetermined operations, such as on / off operation, based on the signal.

FIG. 3 is a circuit block diagram of the system shown in FIG. 2. Among them, 1 is a frequency-mode flicker stimulator, and flicker frequencies of different stimulation points are different. 2 is the visual system of the test subject. 3 is an EEG extraction, amplification and transmission device, which is used to obtain the subject's EEG signals and The signal is amplified and subjected to analog-to-digital conversion, and then the obtained signal is sent to the signal pre-processing device 4. The signal pre-processing device 4 performs pre-processing such as noise reduction on the signal. The electroencephalogram signal analyzer 5 analyzes the signals mainly by spectrum analysis, and finds out the frequency components in the subject's brain electricity corresponding to the frequency of a certain stimulation point in the scintillation stimulator, thereby determining the flicker that the subject is concerned about. Point, and output the corresponding signal to the controller 6. The controller 6 instructs the corresponding equipment to perform corresponding operations according to the preset program according to the signal. The working principle of the EEG signal analyzer 6 has been described in the foregoing, and is not repeated here.

 After the EEG signals with certain characteristics are identified, they can be used as indicators for objective evaluation of each human sensory system. Figures 4 and 5 show a sensory test system based on steady state EEG evoked responses according to the present invention. This system is basically the same as the control system shown in Figs. 2 and 3, except that the control device 6 is replaced with an evaluation device 7 and a stimulation controller 8 is added.

 Taking visual objective detection as an example, the detection steps are:

 (a) According to the different requirements of the visual system measurement, the pre-stimulus before light stimulation is given.

(b) Set the background of this light stimulation.

 (c) Set parameters of light stimulation points (such as spatial position, light intensity, spot size, and duration) for different flicker frequencies. The above steps are implemented by the stimulation controller 8.

 (d) Analysis of the subject's response to different light stimulation points based on the subject's EEG response, combined with the parameters of the light stimulation points (spatial position, light intensity, spot size and duration, etc.) and the human visual system Structure to obtain an objective visual evaluation of this stimulus.

 (e) If you need to design new conditions (such as background and light stimulation point parameters), return to step (b), otherwise step (f).

 (f) According to the objective visual evaluation under various conditions, the total objective evaluation index of the human visual system is obtained.

 As an example of the implementation of the test, we have performed experiments in the laboratory to test the visual acuity of subjects using steady-state visual evoked potentials. The composition of the experimental system is shown in Figure 4.

We designed five flashing square areas on the computer screen, each of which One or more of the same frequency flickers, one of which is in the middle and the other four are located above and below it. During the experiment, as long as the subject looks at a specific middle square region, a frequency component of a specific frequency characteristic of the region will appear in his EEG signal. As the area of the five blinking squares decreases, other specific frequency features appear in his EEG signals. The subject's evoked EEG signal is collected by the EEG signal analyzer and analyzed to detect the tester's vision.

 The EEG extraction and amplification used in the experiment is a ready-made EEG machine. The amplified EEG signal is sent to an EEG signal processor composed of a computer. The computer completes the EEG signal preprocessing and spectrum analysis to obtain the corresponding frequency components. The subject's vision level is then determined by a predetermined computer program.

 The experiment was a success. The above objective visual acuity test accurately gives the visual acuity of different vision subjects.

 Although the present invention has been described in detail by taking visual stimuli and responses as examples, the present invention is not limited to visual stimuli and responses. The stimulator of the present invention may be a sound stimulator, a tactile stimulator, and the like, and the subject's brain electrical steady state response also includes a frequency component corresponding to the frequency of the stimulation signal. Based on this feature, the EEG control and objective evaluation of the corresponding senses can be achieved by analyzing the EEG response of sound stimulation, tactile stimulation, and so on.

 The above detailed description in conjunction with the accompanying drawings is not intended to limit the scope of the present invention. The scope of the invention is only limited by the claims that follow. Without departing from the concept and scope of the present invention, those skilled in the art can easily think of other implementations and applications. These modes or applications should also belong to the scope of the present invention.

Claims

Claim 1. A control method based on EEG steady state response, including:  a. Generate one or more stimulus signals that change at different frequencies and can be sensed by the human senses;  b. Detecting EEG signals of the stimulated human body;  c Analyze the detected EEG signals and extract characteristic physical quantities corresponding to the frequency of a certain stimulus signal as control signals;  d. Control a specific controlled device corresponding to the stimulation signal to perform a predetermined operation based on the control signal.  2. The control method according to claim 1, wherein:  The plurality of stimulus signals changing at different frequencies correspond to a plurality of different controlled devices.  3. The control method according to claim 1 or 2, wherein: the stimulus signal is a visual stimulus signal, and the human senses are visual organs.  4. The control method according to claim 1 or 2, characterized in that: the stimulus signal is an auditory stimulus signal, and the human senses are auditory organs.  5. The control method according to claim 1 or 2, wherein: the stimulus signal is a tactile stimulus signal, and the human senses are haptic organs.  6. The control method according to claim 1 or 2, characterized in that: the analysis comprises performing spectrum analysis on the EEG signals.  7. The control method according to claim 6, wherein: The characteristic physical quantity is the sum of each of the EEG signal spectrums obtained from the spectrum analysis. The amplitude of the peak corresponding to the frequency of the stimulus signal is the largest.  8. The control method according to claim 6, wherein:  The characteristic physical quantity is a harmonic component of a frequency corresponding to each stimulus signal frequency in an EEG signal spectrum obtained by the spectrum analysis.  9. The control method according to claim 1 or 2, characterized in that: said one stimulation signal is of a single frequency.  10. The control method according to claim 1 or 2, characterized in that: said one stimulus signal is a combination of a plurality of frequency signals, and said characteristic physical quantity is more than said combination in an EEG signal. The frequency combination of each frequency signal corresponds to the frequency combination.  11. The control method according to claim 3, wherein:  The visual stimulus signal is an optical signal whose brightness, shape, color, size, spatial position, duration, or a combination thereof changes at a certain frequency.  12. The control method according to claim 3, 11, wherein: the frequency of the visual stimulation signal is 1 to 50 Hz.  13. The control method according to claim 12, wherein:  The frequency of the visual stimulation signal is 4-25 Hz.  14. The control method according to claim 3, 11 or 13, characterized in that: the plurality of visual stimulation signals are a set of light spots flickering at different frequencies on the screen, and each light spot corresponds to a controlled device, respectively. .  15. The control method according to claim 3, wherein:  The one visual stimulus signal is a combination of a plurality of spatially coincident optical signals that change at different frequencies, and the characteristic physical quantity corresponds to the frequency combination of each of the optical signals in the EEG signal and the combination. Frequency combination.  16. The control method according to claim 4, characterized in that:  The auditory stimulation signal is a pure tone with a single frequency. 17. The control method according to claim 4, wherein: The auditory stimulus signal is a composite sound of a certain frequency combination mode.  18. A sensory test method based on a steady state induced response of an electroencephalogram, comprising: a. Stimulating a person's senses with one or more stimulus signals that vary in frequency and can be sensed by the human senses;  b. Detecting EEG signals of the stimulated human body;  c. Analyze the brain signal obtained by the detection, and detect the characteristic physical quantity corresponding to the frequency of the stimulus signal;  d. Evaluate the sensed sensors based on the detected physical quantities corresponding to the frequency of the stimulus signal, stimulus signal strength, and spatial distribution.  19. The sensory test method according to claim 18, wherein: the stimulation signal is a visual stimulus signal, and the human senses are visual organs.  20. The sensory test method according to claim 18, wherein the stimulus signal is an auditory stimulus signal, and the human sense organ is an auditory organ.  21. The sensory test method according to claim 18, wherein: the stimulus signal is a tactile stimulus signal, and the human senses are haptic organs.  22. The sensory test method according to claim 18, wherein: said analyzing comprises performing spectrum analysis on EEG signals.  23. The sensory test method according to claim 22, wherein the characteristic physical quantity is a spectral component in the EEG signal spectrum corresponding to the frequency of each stimulus signal.  24. The sensory test method according to claim 22, wherein the characteristic physical quantity is a frequency corresponding to each stimulus signal frequency and its harmonic components in the EEG signal spectrum obtained from the spectrum analysis. 25. The sensory test method according to claim 18, wherein: The stimulus signal has a single frequency.  26. The sensory test method according to claim 18, wherein: said one stimulus signal is a combination of a plurality of frequency signals, and said characteristic physical quantity is a plurality of combinations of said EEG signals with said combination The frequency combination of the frequency signal corresponds to the frequency combination.  27. The sensory test method according to claim 19, wherein: the visual stimulus signal is an optical signal whose brightness, shape, color, size, spatial position, duration, or a combination thereof changes at a certain frequency.  28. The sensory test method according to claim 19, 27, wherein the frequency of the visual stimulus signal is 1 to 50 Hz.  29. The sensory test method according to claim 28, wherein the frequency of the visual stimulus signal is 4 to 25 Hz.  30. The sensory test method according to claim 19, 27 or 29, characterized in that:  The visual stimulus signal includes a group of light spots flickering at different frequencies on the screen, and their spatial characteristics can be controlled and changed.  31. The sensory test method according to claim 19, wherein the one visual stimulus signal is a combination of a plurality of spatially coincident optical signals that change at different frequencies.  32. The sensory test method according to claim 20, wherein: said one auditory stimulation signal is a pure tone with a single frequency.  33. The sensory test method according to claim 20, wherein: the one auditory stimulation signal is a composite sound of a certain frequency combination mode.  34. A control system based on EEG steady state response, including: a. Stimulators are used to generate the c. A signal processor, configured to analyze the detected EEG signal, and extract a characteristic physical quantity corresponding to a certain stimulation signal frequency as a control signal therefrom;  d. The control device controls a specific controlled device corresponding to the stimulation signal to perform a predetermined operation based on the control signal.  35. The control system according to claim 34, wherein:  The plurality of stimulation signals generated by the stimulator and changing at different frequencies correspond to different controlled devices.  36. The control system according to claim 34 or 35, wherein: the stimulus signal is a visual stimulus signal, and the human senses are visual organs.  37. The control system according to claim 34 or 35, wherein: the stimulus signal is an auditory stimulus signal, and the human senses are auditory organs.  38. The control system according to claim 34 or 35, wherein: the stimulus signal is a tactile stimulus signal, and the human senses are haptic organs.  39. The control system according to claim 34 or 35, wherein the analysis performed by the signal processor includes a spectrum analysis of an EEG signal. 40. The control system according to claim 39, wherein: the characteristic physical quantity is the largest in the peaks in the EEG signal spectrum corresponding to the frequency of each stimulus signal.  41. The control system according to claim 39, wherein:  The characteristic physical quantity is a frequency corresponding to each stimulus signal frequency and its harmonic components in the EEG signal spectrum obtained from the frequency spectrum analysis.  42. The control system according to claim 34 or 35, wherein: said one stimulation signal has a single frequency. 43. The control system according to claim 34 or 35, wherein: The stimulus signal is a combination of multiple frequency signals.  44. The control system according to claim 36, wherein:  The visual stimulus signal is an optical signal whose brightness, shape, color, size, spatial position, duration, or a combination thereof changes at a certain frequency.  45. The control system according to claim 36, 44 wherein the frequency of the visual stimulus signal is 1 to 50 Hz.  46. The control system according to claim 45, wherein:  The frequency of the visual stimulation signal is 4-25 Hz.  47. The control system according to claim 36, 44 or 46, wherein: the plurality of visual stimulation signals are a set of light spots flickering at different frequencies on a screen, and each light spot corresponds to a controlled device .  48. The control system according to claim 36, wherein:  The visual stimulus signal is a combination of a plurality of spatially coincident optical signals that change at different frequencies.  49. The control system according to claim 37, wherein:  The auditory stimulation signal is a pure tone with a single frequency.  50. The control system according to claim 37, wherein:  The auditory stimulus signal is a composite sound of a certain frequency combination mode.  51. A sensory test system based on a steady state induced response of an electroencephalogram, comprising: a. A stimulator for generating one or more stimulus signals that change at different frequencies and can be sensed by human senses;  b. An electroencephalogram signal detector for detecting an electroencephalogram of a human body stimulated by the stimulus signal,  c. A signal processor, configured to analyze the detected EEG signals, and extract a characteristic physical quantity corresponding to the frequency of the stimulus signal therefrom; d. An evaluation device, configured to evaluate the response of the measured sensor to the stimulus signal based on the obtained characteristic physical quantity corresponding to the frequency of the stimulus signal and the spatial distribution characteristics of the stimulus signal. Ability to arrive at an objective evaluation of the senses.  52. The sensory test system according to claim 51, wherein: the stimulus signal is a visual stimulus signal, and the human senses are visual organs.  53. The sensory test system according to claim 51, wherein: the stimulation signal is an auditory thorn, and the human senses are auditory senses.  54. The sensory test system according to claim 51, wherein: the stimulus signal is a tactile stimulus signal, and the human senses are haptic organs.  55. The sensory test system according to claim 51, wherein the analysis comprises performing a spectrum analysis on an EEG signal.  56. The sensory test system according to claim 55, wherein the characteristic physical quantity is a spectral component in the EEG signal spectrum corresponding to the frequency of each stimulus signal.  57. The sensory test system according to claim 51, wherein the one stimulus signal has a single frequency.  58. The sensory test system according to claim 51, wherein the one stimulus signal is a combination of multiple frequency signals.  59. The sensory test system according to claim 52, wherein: the visual stimulus signal is an optical signal whose brightness, shape, color, size, spatial position, duration, or a combination thereof changes at a certain frequency.  60. The sensory test system according to claim 52, 59, wherein the frequency of the visual stimulation signal is 1 to 50 Hz.  61. The sensory test system according to claim 60, wherein the frequency of the visual stimulus signal is 4 to 25 Hz. 62. The sensory test method according to claim 52, 59 or 61, characterized in that On:  The visual stimulus signal includes a group of light spots flickering at different frequencies on the screen, and their spatial characteristics can be controlled and changed.  63. The sensory test method according to claim 52, wherein the one visual stimulus signal is a combination of a plurality of spatially coincident optical signals that change at different frequencies.  64. The sensory test method according to claim 53, wherein the one auditory stimulus signal is a pure tone with a single frequency.  65. The sensory test method according to claim 53, wherein the one auditory stimulus signal is a composite sound of a certain frequency combination mode.